Bone staple storage, inserter, and method for use therewith

ABSTRACT

The invention comprises a fusion implant system for a generally u-shaped bone staple in which the staple is provided on a storage block with the two side legs in an un-splayed position, and an inserter having two triangular shaped pivoting handles has detachable tips that engage the staple on the storage block such that when the handles are aligned one over the other in a congruent position, the tips force the side legs into a splayed configuration at  90 ° and a sliding block holds the handles in this position to allow the staple to removed from the storage block and tamped using the inserter handles into respective bone.

FIELD OF THE INVENTION

The present disclosure relates to an invention, which involvesself-compressive orthopedic bone staples which derive thischaracteristic from the super-elastic and/or shape memory material fromwhich they are made. The staples have a generally U-shaped configurationcomprising a central web and two extending convergent legs, optionallyincluding barbs to hold the staple in position in bone. In accordancewith the invention, the staples are provided in a surgical caddy on astorage block in an unsplayed position in which the legs each form anangle of less than 90° relative to the web member. Also provided in thesurgical caddy is a staple holder/tamp/inserter instrument which is usedto dislodge the staple from the storage block by opening the staple legsto about 90° which releases the staple from the storage block and allowseach of the two legs of the staple to be partially tamped into aseparate bone segment while the staple is held by the inserter. Oncereleased from the inserter, the staple subsequently causes compressionbetween the bone segments to promote fusion between the segments.

BACKGROUND OF THE INVENTION

Despite the importance of fully functional joints for movement andbalance, there are instances in which the pain that can be generated bycertain pathologies justify fusion in order to alleviate on-going pain.It is sometimes necessary or desirable to cause fusion or arthrodesis ofthe bones that form the support structure of the lower leg or hand, forexample, in the case of osteoarthritis, post-traumatic osteoarthritis,ankle arthritis or after failure of previous surgical intervention.Arthrodesis fuses the bones of the joint completely, making onecontinuous bone, and are used to treat conditions in the lower leg andhand, including the hind-foot, ankle, mid-foot, and phalanges.

In accordance with the prior art, fusion surgery involves debridingadjacent bone segments, aligning them as desired and using pins, platesand screws, or rods to hold the bones in the proper position while thejoint(s) fuse. Sometimes, the surgeon will add natural or artificialbone graft in order to assist the fusion process. The surgeon may usegraft from the patient (a piece of bone, taken from one of the lower legbones or the wing of the pelvis) to replace the missing bone. If thealignment of the bone is improper, or if the patient is at risk or isnon-compliant and uses the joint before it is fury healed, the bonessometimes fuse into a position known as “mal-union”. In more severeinstances, the bones do not fully fuse which results in “non-union”.There are two types of nonunion; fibrous nonunion, and false joint(pseudarthrosis). Fibrous nonunion refers to fractures that have healedby forming fibrous tissue rather than new bone. Pseudarthrosis refers tononunions in which continuous movement of the fracture fragments has ledto the development of a false joint.

Prior art hardware for use in arthrodesis includes wires, screws, platesand intramedullary devices. While such devices exist, each is lacking inproviding one or more of the desired precision, stability, fixation, orrelative ease of implantation that an orthopedic surgeon desires forsuch a device. Super-elastic and shape memory bone staples provide ananswer to many of these issues, but a more desirable method of storageand insertion represents an improvement over the prior art.

Thus, it is an object of the present invention is to provide a bonefusion system and surgical method for implanting an implant in a mammal(including specifically humans, and domestic pets and livestock, likehorses, cattle, sheep, goats, dogs, and cats), which allows for fusionof the bones or bone segments in particular of an extremity. The methodincludes using an incision to access the bone or bone segments to befused, debriding and aligning the bones or bone segments, selecting abone staple of the proper size, mounting a bone staple from a storageblock on an inserter by engaging the staple with the tips of theinserter and aligning the handle of the inserter to cause the legs ofthe staple to splay into an open position orthogonal to the web of thestaple which disengages the storage block. Further in this method, aslide inhibits the inserter legs from returning to the un-splayedposition while the staple is in position on the inserter so that thestaple can be tamped into the adjacent bone using the inserter totransmit the force. (Without such a provision, the legs wouldimmediately assert a force to return to the un-splayed position suchthat implanting the staple becomes increasing difficult as the legs moveout of the orthogonal positions.) When the staple is in position in thebone so far as possible using the inserter as a combination holder/tamp,the locking slide is repositioned so that the handles can be returned tothe open position and the staple can be disengaged from the tips of theinserter. The inserter includes a section of the handles, which avow thestaple legs to be implanted in the bone or bones by tamping the handlesand transmitting the force to the staple to anchor it in the bone orbones. The staple can be tamped further into the bone as necessary, andthe wound can be closed. In some instances a further tamp is used toimplant the staple into a position in which the staple web is as closeas possible to (i.e. at or below) the bone surface.

The staple will subsequently apply a compressive force (parallel to theweb member) to the adjacent bone segments to press them into contact asthe staple legs act to return to an unsplayed position in which thestaple legs are at an angle of less than 90° relative to the staple webor bridge.

SUMMARY OF THE INVENTION

An object of the present invention is therefore to provide a system forbone fusion which improves upon the short-comings of the prior art andto provide novel systems and methods for immobilizing bones or bonesegments to be fused in humans and in other animals such as dogs andhorses.

A further object of the invention is to provide a novel instrument forstoring, mounting, and inserting elastic bone staples, along with thesurgical method of implanting the staples and of enabling fusion betweenbones or bone segments. Thus, the present invention has a goal of makingit possible to perform arthrodesis under good operating conditions whilealso making it possible to obtain bone fusion that is particularlystable, strong, precise, and comfortable for the patient and that isparticularly successful under all conditions of bone quality orpathology.

Thus, the invention provides a bone staple system including asuper-elastic shape memory staple having a central web member whichlinks two barbed legs at an un-splayed angle of less than 90° relativeto the central web, and where the staple is provided during surgery on astorage block having a grip and a mounting body that securely cradlesthe staple in the un-splayed position, and an inserter/holder/tamp isused to dislodge the staple from the storage block as size specificinserter tips engage the staple and wherein an congruent alignment ofthe handles of the inserter transfers forces through the tips to thestaple to open the staple legs to 90° where the staple releases thegrooves of the storage block. When the inserter handles are aligned, aspring biased sliding lock slides into position to hold the handles inthe aligned position. In this position the inserter holds the legs ofthe staple, which allows the staple to be inserted into bone by tampingthe flat ends of the inserter handle. The staple is removed from theinserter by releasing the sliding lock and allowing the handles toreturn to the initial position, which disengages the staple from theinserter. The staple is inserted the remainder of the way as isnecessary, and the wound is closed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a bone staple storage and insertion system ofthe present invention illustrating the staple on a storage block and theinserter in an initial engagement of the staple;

FIG. 2 is a front view of the bone staple storage and insertion systemas shown in FIG. 1 with the insertion handles aligned to cause the bonestaple legs to splay outwardly;

FIG. 3 is a front view of the bone staple and inserter of FIG. 1 withthe staple removed from the storage block;

FIG. 4 is a side view of the bone staple inserter of FIG. 1 with thehandles open;

FIG. 5 is a top view of the storage block shown in FIG. 1;

FIG. 6 is a front view of the storage block shown in FIG. 1;

FIG. 7 is a side view of the storage block shown in FIG. 1;

FIG. 8 is a top side view of the bone staple of FIG. 1;

FIG. 9 is a front view of the bone staple of FIG. 1;

FIG. 10 is an exploded view taken from a first side of the bone stapleinserter of the present invention illustrating spring systems that biasthe handles apart, and the lock towards a locked position; and

FIG. 11 is an exploded view of the bone staple inserter of FIG. 10 takenfrom the other side.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a first embodiment of a generally U-shaped bonestaple 10 made from a super-elastic and shape memory material, such asNitinol ASTM 2063 which is super elastic between the temperatures of0-15° C. and above (i.e. at operating room temperatures). Multiple sizesof the staple are provided ranging from 8 to 25 millimeters. Typically,the staples are provided in a variety of widths ranging in millimeterincrements from 8 to 25, and varying in leg length in millimeterincrements from 8 to 24 millimeters, and in corresponding thicknessbeginning at 1.6 millimeters and increasing to 1.9 or 2.0 or even to 2.5millimeters for the largest size. An entire system may comprise 20 to 80staples with multiple versions provided at each of 5 to 10 differentsizes. The staple is pre-loaded in an un-splayed configuration on astorage block 20. As shown in FIGS. 8 and 9, in the un-splayedconfiguration, the side legs 14 of the staple 10 each form an angle ofless than 90°, and preferably at an angle of from 70° to 85°, morepreferably at from about 75.5° to about 81°, and most preferably at fromabout 76.5° to about 80° relative to the base web 12 of the staple. Thelegs can also include a series of unidirectional barbs 15 which angleoutward toward the web end of the staple help to hold the staple inposition in the bone after implantation.

The storage block 20 is shown in FIGS. 5-7 from the side, front and edgerespectively. The storage block includes a hand grip 22 which isintegral with a storage body 23 that includes a front face 24 having twogrooved areas 25 which form ramps (of from 70° to 85°, more preferablyat from about 75.5° to about 81°, and most preferably at from about76.5° to about 80° relative to the front face 24 of the body 23 or whichcorrespond to the angle of the staple legs relative to the staple web)to capture the legs 14 of the staple at the un-splayed angle. It ispreferable that the staple fits tightly on the storage block so that itis unlikely to come off without the use of the staple inserter providedwith the system.

FIG. 1 further illustrates the staple 10 engaged by an inserter 30. Theinserter 30 includes a pair of right and left scissoring handles 32connected by pivot member 33 and which are in a first position (open toan angle relative to each other or from the leading edge of one handleto the opposing edge of the other handle of from about 0° or with thehandles fully aligned in the splayed position, to about 7.5° or with thetips touching in the un-splayed position) in which the detachable pairof right and left tips 34 of the inserter 30 engage the inner cornersformed at the junction of the inner web member 12 and the legs 14 of thestaple. In this position, the staple 10 is engaged by the posts 38 onthe tips in the space between the staple web or bridge 12 and the frontface 26 of the storage block 20, but there is not sufficient tension ofthe legs 14 of the staple to cause them to open into a substantiallyperpendicular position relative to the web member 12, The inserterincludes a spring member 50, which biases the handles into the openposition, and opposes the closing force as the handles are squeezedtogether by a single hand. The storage block 20 includes a roundedgroove 22 which forms a comfortable place for the fingers, and a neckedarea 28 which allows the user to see that the staple is fully seated.

When the surgeon is ready to implant the staple, he or she (or asurgical assistant) uses the inserter to engage the staple asillustrated and typically with one hand squeezes the handles 32 of theinserter 30 together to the point at which they align, and the staplecan be removed from the storage block which is held in the other handand without releasing the handles or the staple from the inserter, thestaple can be mostly implanted into the bone segments (i.e, up to about2 millimeters from the bone surface before the staple is released fromthe inserter).

The handles have a generally triangular shape with undulating fingergrips that facilitates finding the alignment position by simplysqueezing the handles inward and together. This causes the opposite endsof the inserter and the detachable inserter tips 34 to open outward andapply a pressure to the staple legs 14 so as to open them each to asubstantially perpendicular position relative to the inner web of thestaple 12. Specifically, the inserter has a right tip 35 and a left tip36 each of which has an inner engagement post 38 that opposes theforward surface of a web abutment member 39 on the tip across a gap thatis sized to accept the width of the inner web 12 of the staple 10. Inuse, the web abutment members 39 hold the inner web 12 of the staple 10in a relatively straight position while the respective inner engagementpost 38 presses its respective leg outward. At the point where thestaple legs 14 are about perpendicular to the staple web, a sliding lock40 on the right handle 32 of the inserter, which is biased by a spring41 housed in a recess 43 in the right handle and the back side of thesliding lock, toward the inserter tips simultaneously (and without theneed for the user to separately manipulate the sliding lock) springstowards the pivot member or screw 33. The sliding lock 40 has a post 42that prevents the two handles 32 from returning to their originalpositions with the right handle open to the right of the left handle.While the handles are open and the staple is splayed, the handles couldstill be pulled apart to further splay the staple. The sliding lock onlyprevents the inserter from returning to its original position on therespective right and left side but still allows the handles to keepsplaying the staple if they are pulled apart such that the right handleis open to the left side and the left handle is open to the right side.Thus, it is still possible, if it is medically warranted to open thelegs 14 of the staple 10 past 90°.

In this “splayed” position, the staple legs 14 disengage the angledsides 22 of the storage block 20. Using the inserter 30 as a holder, thestaple 10 can thus be removed from the storage block 20 in an openedposition ready for deployment into bone segments. Further, when thehandles 32 of the inserter align into congruence, the sliding lockmember 40 slides into position and post member 42 inhibits the handlesfrom being pressured by the legs 14 of the staple back into the firstposition. Each of the handles 32 include a rear section 37, and when thehandles are aligned these sections can be used to tamp the staple intoposition in the bone by transmitting a force through the inserter to thesharp staple tips 18. To remove the inserter and tips from the staplethe sliding lock is pulled away from the pivot screw and the handleswill return to their original position.

As a further aspect of the invention, the staples are provided in avariety of sizes with outside web lengths ranging from 8 to 25millimeters and outside leg lengths ranging from 8 millimeters to 24millimeters, and accordingly, corresponding tips are provided toaccommodate each of these sizes. The inserter is provided on each sidewith a ball detent 51 that helps to hold each respective tip in itsposition on the inserter. As can be seen in FIG. 10, the handles aredesigned to interfere past the pivot to inhibit the forces on the tips.

A surgical technique in accordance with the invention is described asfollows:

Surgical Technique

Step 1: Incise the area involving the area to be fused to provide accessto the bone or bone segments. Excise or debride the adjacent surfaces ofthe bone to be fused. Align and fix the bone using the provided k-wire,

Step 2: Using a sizer provided in the surgical caddy with the system ofthe present invention determine the proper size of bone staple to beused by marking the locations for the staple legs with the correspondinglegs of the sizer.

Step 3: Using the sizer, mark the respective placement of the staplelegs, and using the provided drill guide or k-wire, drill pilot holesfor the staple legs.

Step 4: Prepare the inserter by placing the right and left tip of theproper size on the respective end of the inserter, being sure that thetip clicks into position. Using one hand engage the storage block andpre-mounted staple of the selected size, and with the other hand engagethe staple web/leg interface on either side with the inserter tips. Thestaple web should nestle between the tip face and a tip block on eitherside.

Step 5: Using a single hand, squeeze the handle inwardly until they arealigned, causing the legs of the staple to splay outwardly and disengagethe storage block as can be easily viewed at the necked portion of theblock. With the handles aligned, the sliding lock will pop into positionto hold the legs of the staple in the splayed position at 90°.

Step 6: Using the inserter to maintain the splayed position of thestaple legs, position the staple legs in the pilot holes and now use theinserter as a tamp by tapping on the flat proximal ends of the handleswith a mallet to transmit the force through the staple to lodge it intothe bone.

Step 7: Disengage the inserter from the staple by disengaging thesliding lock and allowing the inserter handles to separate to theiroriginal position. Using the provided tamp finish implanting the stapleinto the bone segments as is necessary.

Step 7: Check the alignment using fluoroscopy and close the incision.

While in accordance with the patent statutes the best mode and preferredembodiment have been set forth, the scope of the invention is notlimited thereto, but rather by the scope of the attached claims.

1-18. (canceled)
 19. A fusion implant system comprising a staple havinga central web and a first leg and a second leg where each of the firstleg and the second leg form an angle of from 70 degree. to 85 degree.relative to the central web, and an inserter having a first handlejoined by a pivot to a second handle and having a right tip and a lefttip which capture the staple wherein the first and second leg of thestaple splay to a perpendicular position relative to the central webwhen the first handle is in a congruent opening alignment relative tothe second handle.
 20. The fusion implant system as set forth in claim19 wherein the first handle and the second handle have the same shapeand the shape is symmetrical about a long axis.
 21. The fusion implantsystem as set forth in claim 20 wherein the first handle and the secondhandle each include a proximal surface which faces away from the rightand the left tips and the proximal surface is perpendicular to the longaxis of the first handle and the second handle in the opening alignmentand is structured to transmit a tamping force to the staple in use. 22.The fusion implant system as set forth in claim 19 wherein the firsthandle is in a scissoring relationship to the second handle and whereinthe inserter further includes a sliding lock member which is biased tospring into a locking position when the first handle and the secondhandle are in the opening alignment.
 23. The fusion implant system asset forth in claim 22 wherein the sliding lock member acts to hold thestaple legs in an open position perpendicular to the staple web.
 24. Thefusion implant system as set forth in claim 19 wherein the staple legsare each provided at an angle of from 75.5 degree. to about 81 degree.relative to the web of the staple.
 25. The fusion implant system as setforth in claim 19 wherein a plurality of the staple are provided in thesurgical caddy in a variety of sizes and a corresponding variety ofpairs of right and left tips are provided in the surgical caddy in avariety of sizes.
 26. The fusion implant system as set forth in claim 25wherein the inserter includes a first ball detent and a second balldetent that holds the right tip on the left handle and the left tip onthe right handle.
 27. The fusion implant system as set forth in claim 26wherein one of the handles include a first recess that houses a springand the other of the handles includes a stop that the spring actsagainst to bias the handles apart.
 28. A fusion implant system as setforth in claim 27 wherein each of the staple legs includes a barb thatis pointed toward the open end of the leg, and widens toward the web ofthe staple.
 29. A fusion implant system as set forth in claim 19 furtherincluding a storage block in which the staple is stored in a position inwhich the legs form an angle of less than 90 degree. relative to the webof the staple and the storage block includes a finger grip spaced fromthe staple web.
 30. A fusion implant system as set forth in claim 19wherein the staple comprises a super-elastic and shape memory material.31. A fusion implant system as set forth in claim 30 wherein thematerial is nitinol.
 32. A fusion implant system as set forth in claim19 wherein the material meets the standards set forth in ASTM F2063. 33.A method of enabling a surgery comprising providing a surgical caddyincluding a fusion implant system comprising a plurality of staples in avariety of sizes, each staple having a central web and a first leg witha first set of barbs and a second leg with a second set of barbs, astorage member which houses the staple in a position with the first andsecond leg at an angle of from 70 degree. to 85 degree relative to thecentral web, and an inserter having a first handle having a first shapejoined by a pivot to a second handle having a shape that is the same asthe first shape, and the first handle having a first tip and the secondhandle having a second tip which cooperate to capture the staple whereinthe first and second leg of the staple splay to a perpendicular positionrelative to the central web when the first handle is in a congruentalignment over the second handle.
 34. A method of performing a surgerycomprising using a staple system wherein the staple has a central weband a first leg with a first set of barbs and a second leg with a secondset of barbs and the staple is stored on a storage member which housesthe staple in a position with the first and second leg at an angle offrom 75.5 degree. to about 81 degree. relative to the central web, andusing a staple inserter having a first handle having a first triangularshape joined by a pivot to a second handle having a shape that is thesame as the first shape, and the first handle having a first detachabletip and the second handle having a second detachable tip which cooperateto capture the staple wherein the first and second leg of the staplesplay to a perpendicular position relative to the central web when thefirst handle is moved using a single hand to a congruent alignment overthe second handle and a sliding lock springs into a position to lock thehandles in the congruent alignment whereby the staple can be tamped intoadjacent bone segments using tamping surfaces on the end of the firsttriangular shaped handle and the second triangular shaped handle.